Conventionally, in a semiconductor manufacturing process or a liquid crystal manufacturing process, a plasma device such as a film forming device for forming a thin film on an object such as a semiconductor wafer or a glass substrate, or an etching device for applying microfabrication to an object is employed. In the film forming device, raw material gas is supplied into a reaction chamber, and this gas chemically reacts.
Accordingly, a thin film is formed on an object. Additionally, in the etching device, halogen type corrosive gas is supplied into a reaction chamber as raw material gas, and this gas is converted into plasma to become etching gas. Accordingly, microfabrication is applied to the object.
As disclosed in Japanese Unexamined Patent Application Publication No. 2000-195807, a plasma device has a gas nozzle for supplying gas into a reaction chamber. This gas nozzle includes a columnar main body including a ceramic sintered body having a through hole through which gas flows.
In a case of employing the plasma device, when a surface of the ceramic sintered body configuring an inner wall of the through hole is exposed to plasma-converted gas in the reaction chamber, the surface is damaged and particles may falloff from this surface. When these particles adhere to the object, failure is likely to occur in the object.